Born as Stephen Joshua Sondheim into a prosperous business Jewish family in New York City, he had no formal religious education or association, did not have a Bar Mitzvah, and reportedly did not set foot in a synagogue until he was 19. In 1950, he graduated magna cum laude from Williams College in Williamstown, Massachusetts.

He is a gay composer, lyricist, and writer. His early interest in the American musical was encouraged by Hammerstein, and he achieved success first as a witty and sophisticated lyricist of Bernestein's West Side Story and later as a composer of musical.

As a friend of Hammerstein's son, Sondheim was able to ask the famous librettist for an evaluation of his first stage work, a high school production produced at the age of 15. As a young man, he studied lyric writing with Oscar Hammerstein 2d, and early in his career he wrote lyrics for Leonard Bernstein 's "West Side Story" (1957) and "Candide" (1974), and collaborated with Jule Styne. Hammerstein's critical evaluation of "By George" initiated a four-year relationship that was decisive in formulating the young artist's style. As Hammerstein's personal assistant, Sondheim gained entry into the world of professional theater.

While attending Williams College he performed duties in the preparation and rehearsals of the Rogers and Hammerstein productions of "South Pacific" and "The King and I." Upon graduation he won the Hutchinson Prize, which enabled him to study composition at Princeton University with Milton Babbitt.

He is known for his collaborations with Richard Rogers on "Do I Hear a Waltz" (1965). Sondheim's partnership with the director/producer Hal Prince resulted in Tony Awards for Best Musical Scores for three consecutive years (1971-1973), and "Pacific Overtures" (1976) was hailed as a landmark in American musical theater because of its masterful use of traditional Japanese theater elements. In 1984, Sondheim paired himself with James Lapine to put together "Sunday in the Park with George," a musical inspired by a Georges Seurat painting.

Meryle Secrest's "Stephen Sondheim: A Life" (1998) describes his working relationship with Leonard Bernstein and tells of his dating women while having relations with men. In 1991, he said he fell in love for the first time in his life, to Peter Jones, a young writer. Sondheim is a six-time Tony Award winning composer/lyricist.

Stephen has written songs like Send in the Clowns and Somewhere. This last song is adopted by the gay population as a sort of anthem. His Broadway shows include Company, A Funny Thing Happened on the Way to the Forum, and A Little Night Music. He also cowrote the screenplay for The Last of Sheilah with gay actor Anthony Perkins. Sondheim was the recipient of Kennedy Center Honors in 1993, winner of a 1985 Pulitzer Prize for Drama, and Tony-award winner.